@article {1391,
	title = {CPCO(CO)(2)-catalysed cyclotrimerisation of alkynes in supercritical carbon dioxide},
	journal = {Journal of Organometallic Chemistry},
	volume = {632},
	number = {1-2},
	year = {2001},
	note = {<p>Sp. Iss. SI474JKTimes Cited:21Cited References Count:43</p>
},
	month = {Aug 24},
	pages = {113-118},
	abstract = {<p>The reactivity of mono-substituted HC=CR (R =Ph. a; CH2OH, b; CH2CH2CH2CH3, c) and di-substituted RC=CR (R = CH2CH3, d; CO2CH3, e; Ph. f) acetylenes was studied in supercritical carbon dioxide (scCO(2)) using the easily available complex CpCo(CO)(2) as catalyst. The reaction of phenylacetylene produced a mixture of the isomeric cyclotrimers 1,3,5- (2a) and 1.2,4-triphenylbenzene (2a {\textquoteright}). in a 1:5 ratio, and traces of cobaltcyclopentadienone complexes CPCO(eta (4)-C4H2[Ph](2)CO) (6a, mixture of isomers). The possible product formed by the incorporation of CO, to alkynes, i.e. diphenylpyrone (7a) was not observed. The reaction of the cobaltacyclopentadiene complex CpCo(1.4-sigma -C-4[Ph](4))(PPh)(3) (8f), in scCO(2), was performed. No insertion of CO2 into the Co-C a-bond to form tetraphenylpyrone (7f) by reductive elimination was observed, instead the cobaItcyclobutadiene Complex CpCo(eta (4)-C-4[Ph](4)) (9f) was formed. In the reactions with other alkynes, lower yields were obtained in general, except in the cyclotrimerisation of the highly activated alkyne, propargyl alcohol (b). Reaction of the non-activated alkynes, 1-hexyne (c) and 3-hexyne (d), produced complex mixtures of cobalt complexes in low yield in which the alkyne was coordinated to cobalt. Finally, the highly hindered diphenylacetylene (f) gave a mixture of the known Complexes CpCo(eta (4)-C-4[Ph](4)) (9f) and CpCo(eta (4)- C-4[Ph](4)CO) (6f) in agreement with the results observed in conventional organic solvents. (C) 2001 Elsevier Science B.V, All rights reserved.</p>
},
	keywords = {alkyne, cobalt metallocycles, cobaltacyclopentadiene, complexes, cpco(co)(2), cyclotrimerisation, cyclotrimerizations, homogeneous catalysis, hydrogenation, olefins, one-step, photochemistry, room-temperature, supercritical co2},
	isbn = {0022-328X},
	url = {<Go to ISI>://000171103200014},
	author = {Montilla, F. and Aviles, T. and Casimiro, T. and Ricardo, A. A. and da Ponte, M. N.}
}
